IS 10790-1: Methods of sampling of steel for prestressed and reinforced concrete, Part 1: Prestressing steel

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IS 10790-1 (1984) : Methods of sampling of steel for
prestressed and reinforced concrete. Part 1: Prestressing
steel [CED 54: Concrete Reinforcement]

Jawaharlal Nehru
'Step Out From the Old to the New"

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Satyanarayan Gangaram Pitroda
Invent a New India Using Knowledge

Bhartrhari — Nitisatakam
''Knowledge is such a treasure which cannot be stolen"

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PROTECTED BY COPYRIGHT

IS 110790 ( Parti J -1984

( Reaffirmed 2005 )

Indian Standard

METHODS OF SAMPLING OF STEEL FOR
PRESTRESSED AND REINFORCED CONCRETE

PARTI PReSTBESSINQ STEEL

UDC 666 982*4 : fl69-l4'018'2?5'5 : 62fl 1 i3

® Copjrighi 1984

INDIAN STANDAHI>S INSTITUTION

MANAK RHAVAH, * BAHADUR SHAH 2 A FAR MARCj

IS : 107iM) ( Part 1 ) - 1984

Indian Standard

METHODS OF SAMPLING OF STEEL FOR
PRESTRESSED AND REINFORCED CONCRETE

PART 1 PRESTRESSING STEEL

Building Materials and Components Sampling Sectional

Committee, BDC 31

Chairman Representing

Dr Mohan Rai Central Building Research Institute (CSIR),

Roorkee

Members

Shri S. K. Goswami ( Alternate to
Dr Mohan Rai )
Shri S. K. Banerjee National Test House, Calcutta

Shri Bimlesh Kumar Export inspection Council of India, New Delhi

Shri J. P. Maikhuri ( Alternate )
Shri Y. C. Gokhale Central Road Research Institute ( CSIR ), New

Delhi
Shri P. S. Gopinath Central Public Works Department, New Delhi

Surveyor of Works ( NZ ) ( Alternate )
Shri S. C. Kumar Small Industries Service Institute, Trichur

Shri K. V. K. Raju ( Alternate )
Shri M. V. Lakshmanaswamy Indian Statistical Institute, Bombay

Dr a. G. Majdhava Rao Structural Engineering Research Centre ( CSIR ),

Madras
Shri D. S. Ramachandra Murthy
( Alternate )
Shri S. M. Mittal Railway Board ( Ministry of Railways ), New

Delhi
Deputy Director Research
(B &S )-I {Alternate)
Shri S. S. Rajput Forest Research Institute and Colleges, Dehra

Dun
Shri K. S. Srinivasan National Buildings Organization, New Delhi

Shri T. R. Bhatia ( Alternate )
Dr V. V. SuBBA Rao Cement Research Institute of India, New Delhi

Shri K. H. Babu ( Alternate )
Shri G. Venkatesulu Ministry of Shipping and Transport, New Delhi

Shri Prafulla Kumar ( Alternate )
Shri D. S. Ahluwalia, Director General, ISI ( Ex-officio Member )

Director ( Statistics )

Secretary
Shri A. K. Talwar
Deputy Director ( Statistics ), ISI

( Continued on page 2 )

(§) Copyright 1984

INDIAN STANDARDS INSTITUTION

This publication is protected under the Indian Copyright Act (XIV of 1957) and
reproduction in whole or in part by any means except with written permission of the
publisher shall be deemed to be an infringement of copyright under the said Act.

IS: 10790 (Part 1)*19S4

( Continued from page 1 )

Building Steels and Steel Products Sampling Subcommittee,
BDC 31 : 1

Members Representing

Shri M. G. Shade The Tata Iron and Steel Co Ltd, Jamshedpur

Shri S. a. Haque ( Alternate )
Shri M. R. Doctor Special Steels Ltd, Bombay

Shri S. G. Joshi ( Alternate )
Shri S. K. Goswami Central Building Research Institute ( CSIR ),

Roorkee
Shri G. K. Majumdar Hindustan Prefab Ltd, New Delhi

Shri M. Kundu ( Alternate )
Shri P. R. Natarajan Structural Engineering Research Centre ( CSIR ),

Madras

Shri N. Jayaram ( Alternate )
Dr N. Raghvendra Cement Research Institute of India, New Delhi

Shri H. K. Julka ( Alternate )
Shri H. N Subha Rao Hindustan Steel Works Construction Ltd,

Calcutta

ShRI J- Ghatak ( Alternate )

IS : 10790 ( Part 1 )- 1$84

Indian Standard

METHODS OF SAMPLING OF STEEL FOR
PRESTRESSED AND REINFORCED CONCRETE

PARTI PRESTRESSIIMG STEEL

0. FOREWORD

0.1 This Indian Standard ( Part 1 ) was adopted by the Indian Standards
Institution on 19 March 1984, after the draft finalized by the Building
Materials and Components Sampling Sectional Committee had been
approved by the Civil Engineermg Division Council.

0.2 This Indian Standard has been prepared with a view to unifying the
quality control and sampling provisions applicable to all types of
prestressing steel used in prestressed concrete. Some broad guidelines
regarding the provisions for process control have also been indicated
besides giving an objective sampling procedure helpful in large scale
transactions.

0.3 Such process control and sampling procedures will help in the
development of adequate quality assurance system in the manufacture
and also in assuring adequate protection to the users against poor quality.
Further, proper quality control during the process of manufacture would
substantially reduce quality fluctuations of the various characteristics and
thus, ensure supply of uniform quality of prestressing steels. For effective
process control, the use of statistical quality control techniques is
imperative, for which helpful guidance may be obtained from IS : 397
(Parti )-1972*, IS : 397 ( Part 2 )- 1975* and IS ; 397 ( Part 3 )-I980*.
The purchasing organizations need guidance in economic and effective
sampling inspection of the lots of materials being received by them
to evaluate their quality before their actual use. The sampling procedures
recommended in this standard, therefore, include provisions both for
process control and lot inspection.

0.4 The reinforcing steel used in reinforced concrete is separately covered
in Part 2 of this standard.

0.5 Itt reporting the results of test or analysis, if the final \alue, observed
j:)t .caJoulated,. is to be rounded off, it*shdi-be done in accordance with
4a:>l960t^ ,\

'y* '*Meth63 jpbf ^btisiical quality contp^

Pari 1 Coiitfbl charts fofvariafcles jJ^rj/V^v/^/o/i ). ' * •

Part 2 Coiittdl charts for attlribUtes arid cotiiif c)f defeats (^/*j/ revision ); ■
Part 3 Special control chdftsr - ■- . - -

titules for rounding off numerical Values ( revised ).

IS: 10790 (Parti) -1984

1. SCOPE

1,1 This standard ( Part 1 ) prescribes the methods for sampling, sample
sizes and the criteria for cx)nformity for prestressing steel used in prestres-
sed concrete. Broad outlines with regard to the controls to be exercised
during the manufacturing process have also been indicated.

2. TERMINOLOGY

2*0 For the purpose of this standard, the following definitions shall
apply.

2.1 Acceptance Number — The maximum allowable number of defectives
in the sample for acceptance of the lot.

2.2 Coll — One continuous length in the form of a coiL

2.3 Bar — A rolled rod or bar of steel of circular cross section.

2.4 Item — A coil or a bar on which inspection will be performed.

2.5 Lot — The quantity of material of the same grade and nominal size
manufactured from steel fully tested in respect of physical, chemical and
surface characteristics and processed under similar conditions shall
constitute a lot.

2.6 Lot Size — The number of items in a lot.

2.7 Mean (J) — The sum of test results divided by the number of test
results.

2.8 Ran^e (R) — The difference between the maximum and minimum
values of test results in the sample.

2.9 Sample — Collection of coils or bars of prestressed steel selected for
inspection and testing from a lot.

2.10 Sample Size — Number of items in the sample.

2.11 Acceptable Qualify Level ( AQL ) — The maximum percent defective
that, for the purpose of sampling inspection, can be considered satisfactory
as a process average.

3. PROCESS INSPECTION

3.1 The object of inspection by the purchaser is to ensure conformity of
the tnaterial offered to him to the specification requirements, whereas the
inspection done by the m^nufacttifdr during the t)f6dtiction is not only
to ensiire the conformity to rfcleV^nt ^i^ecificatibiis, but also ' to maintain
overall uniform quality. For pfdce^S control, the manufacturer sh^^uld
test representative sample? of the matefial at regular intetvals, duriflg
manufacture to control the quality VatiatiOn at .variotjs manufacturing
stages. The impedioti le^^ls, gi^^eh in tablfe 1 ma}^ serve as a guid6 for
routitte control ov^r the manufacturing process., ,..

IS : 10790 ( Part 1 ) - 1984

(1)

(2)

i)

Raw material

>i)

After patenting

iii)

Before final pass in

drawing

iv)

After final pass in

drawing

V)

After stress relieving

TABLE 1 PROCESS INSPECTION LEVELS

( Clause 3.1 )

Sl No. Stage Recommended Frequency of

Inspection and Testing

(3)
One coil from every heat/cast received to be

tested for chemical, physical and metallurgical

characteristics
Two coils to be tested for every patenting batch/lot
Dimensional check every four hours

Dimensional check and UTS for each coil

Every fifth coil for dimensions, proof stress, UTS,
elongation ductility and indentation. One coil
every month for relaxation and susceptibility to
stress corrosion

3.2 The manufacturer should maintain control of various characteristics of
the prestressing stesl on the basis of the following considerations.

3.2.1 Following an unsatisfactory test result, the manufacturer should
take all necessary steps to rectify the deficiencies and shortcomings in the
process. Products which do not satisfy the requirements are to be
segregated.

3.2.2 Results of the inspection and testing should be recorded and
evaluated statistically. The records may be preserved for adequate period
of time say 2 to 3 years so that they can be referred to in case of
difficulties and complaints.

3.2.2.1 The scrutiny of the test results may be carried out with the aid
of statistical methods adopting the variables or attributes approach as
appropriate. The variables approach shall normally be applied for proof
stress, tensile strength, elongation, weight, dimensions, rolling and cutting
tolerances and chemical requirements. The attributes approach might be
applied in respect of bending test and visual characteristics. For this
purpose, reference may be made to IS : 7200 ( Part 1 )-1974*, IS : 7200
( Part 2 )-1975t, IS : 6200 ( Part 1 )-1977t IS : 6200 ( Part 2 M977§,
IS : 7300-197411 and IS : 7600-197511.

3.3 On the basis o^ \h.Q process inspection data, the manufacturer may
issue relevant test certificate to proVe the conformity of a lot ^ to the
reqtiirefndnts of any specification, ;, "■'/' ''**

*PreS!esit2itioti of. statistical data: Part 1 Tabulation and .summarization.
tPi^entfttion of statistical d&ta: Part 2 iJiagratnmatic representation of data,
ist^tistical tests of sign'ificaiice: Part i /-. Normal and i^-tests {first te^isiott).
iSf^tisticai tests of Significaride: Part 2 A:^-test {first revision ).
yMethods of regtesSioft atid correlation,
If Analysis of variance.

IS:10790(Partl)-1984

3-3.1 When such test certificate cannot be made available to the
purchaser or when the purchaser so desires, the procedure laid down
in 4 shall be followed for judging the conformity or otherwise of a lot to
the requirements of relevant specifications.

4. LOT INSPECTION

4.1 Lot — The quantity of material of the same grade and nominal size
manufactured from steel fully tested in respect of physical, chemical and
surface characteristics and processed under similar conditions shall
constitute a lot.

4.2 The samples shall be selected and examined for each lot separately
for ascertaining their conformity to the requirements of the relevant
specifications.

4.3 Scale of Sampling and Criteria for Conformity
4.3.1 VisuaU Dimensional and Weight Characteristics

4.3.1.1 The number of items to be selected for visual, dimensional
and weight characteristics as mentioned in the respective Indian
standard specification depend upon the size of the lot and shall be in
accordance with Table 2. These items shall be selected from the lot at
random. In order to ensure the randomness of selection, procedures given
in IS : 4905-1968* may be followed.

TABLE 2 SCALE OF SAMPING AND ACCEPTANCE NUMBER FOR
VISUAL, DIMENSIONAL AND WEIGHT CHARACTERISTICS

{Clauses 4^A.lA•^^•2 and 4,^.\3 )

Lot Size For Visual Characteristics For Dimensional and Weight

Chraracteristxcs

Sample Acceptance r-

Size Number Sample Acceptance'

Size Number

(1) (2) (3) (4) (5)

Up to 25 8 5

26 to 50 13 18

51 to 100 20 1 13 1

101 to 150 32 2 20 1

151 t6300^ 50 > . ^T 32 2

361 to .500 to 5 ... JO ,:. , .. . ^^

501 and above 125 7 80 5 '*

value

Note — The above sampling plan hSs an assbchtisd AQL'of 2*5' i^efeent; This
iieof AQLwill hold good getiefaily in ca§eof ^arge^l^^^ ' -^^ -

^Methods for random sampling.

is : 10790 (Parti). 1984

4.3.1.2 Each item selected according to col 1 and 2 of Table 2 shall be
inspected for visual characteristics and freedom from defects. Any item
failing to meet any of the requirements shall be considered as defective. If
the number of defectives fourtd in the sample is less than or equal to the
corresponding acceptance number given in col 3 of Table 2, the lot shall
be considered as conforming to the requirements of visual characteristics.

Note — In case of those lots which have been found unsatisfactory, all the items
in the iot may be inspected for visual characteristics and the defectives may be
removed, if agreed to between the purchaser and the supplier,

4.3.1.3 The lot which has been found satisfactory with respect to
visual characteristics shall be further inspected for dimensional and weight
requirements. The number of items required for this purpose shall be
taken at random in accordance with col I and 4 of Table 2. These may be
taken from those items which have been found conforming to visual
characteristics. If the number of defectives found in the sample for weight
or dimensional requirements is less than or equal to corresponding
acceptance number ( see col 5 of Table 2 ), the lot shall be considered as
conforming to the requirements of the relevant specifications; otherwise
not.

4.3.1.4 The lot which has been found satisfactory in visual, dimensional
and weight characteristics shall be further tested for physical and chemical
characteristics according to 4.3.2 and 4.3.3.

4.3.2 Physical Characteristics

4.3.2.1 The specimens for physical characteristics like tensile strength,
proof-stress, ductility, elongation, relaxation and susceptibility to stress
corrosion as given in the respective Indian Standard specification, shall be
taken in such a manner that it represents the material and shall be so
prepared that it conforms to the relevant specification to ensure uniformity
of test procedure.

4.3.2.2 The number of items required for tensile strength, proof-stress
ductility, and elongation shall be in accoxdance with col 1 and 2 of
Table 3. These may be taken from those items which have been found
satisfactory in visual, dimensional and weight requirements. From each
of the items so selected, the required number of test specimens shall be
prepared for conducting the tests specified.

4.3.2.3 When tests for relaxation and susceptibility to stress corrosion
are required to be carried, six specimens obtained from the items selected
in 4.3.2.2 shall be tested. In case the number of items is less than six,
additional items may be selected from the lot at random.

Is : 10790 ( Part 1 ) - 19^4

TABLE 3 SCALE OF SAMPLING FOR PHYSICAL AND CHEMICAL TESTS

( Clauses 4.3.2.2 and 4.3.3.1 )

Number of Items in a Lot Number of Items to be Selected

(1) (2)

Up to 50 2

51 to J50 3

151 to 500 5

501 and above 8

4.3.2-4 For ascertaining the conformity of the lot in respect of tensile
strength, proof stress and elongation, the following procedure shall be
adopted:

a) When two items are selected from a lot and tested, the lot shall
be considered as conforming to the requirements of tensile
strength, proof stress and elongation if both the samples pass
in each of the tests.

b) When the numbe_r of items selected from a lot is three or
more, the mean { x) and range {R) are calculated from the test
results for each characteristic. The lot shall be considered as
conforming to the specification if the value of (^—0*4 i? ) is
greater than or equal to the corresponding minimum specifica-
tion limit of the characteristic in the relevant specification.

4.3.2.5 The lot shall be considered as conforming to the requirements
of ductility test, relaxation test and susceptibility to stress corrosion test
if each of the test results is found to be satisfactory.

4.3.3 Chemical Characteristics

4.3.3.1 The number of items required for chemical analysis shall be
taken at random in accordance with col 1 and 2 of Table 3. These may be
taken from those items which have been found conforming to visual,
dimensional and weight requirements.

4.3.3.2 From each of the items so selected, drilling shall be taken and
a composite sampie of these drillings shall be made. The lot shall be
considered as complymg with the requirements of various chemical
constituents, if the analysis made on the composite sample conforms to
the requirements of the relevant specifications.